An optical rotatable scan detection device is a device for performing non-contact scan detection using collimated light beam through a triangulation method, a Time of Flight (TOF) method and the like. Currently, an optical rotatable scan detection device based on the Time of Flight method generally includes a light emission module, an optical lens, a chip for receiving and processing signals, a motor, a bearing and an electrically conductive slip ring. The light emission module emits a detection light beam. The optical lens is located on a light path of the light emission module. The collimated light beam is incident onto a surface of a detected object, and reflected by an obstacle into a reception chip. The reception chip can calculate a distance between the detected object and the optical rotatable scan detection device based on a time between emission and reception of the detection light beam, a phase difference between the emitted detection light beam and the received detection light beam and the known light velocity. In this type of device, the light emission module, the optical lens, the light reception module and the like, which are used for ranging, are mounted on a platform which can rotate continuously, thereby implementing scanning using the collimated light beam. Environment distance signals covering 360 degrees can be acquired with rotation of the motor.
In the conventional technology, the ranging device needs to perform multiple data samplings for measuring a distance from a same detection region. For example, in the calculation procedure of a phase based Time of Flight method, four data samplings are required for measuring a distance from a detection region, so as to acquire an accurate detection distance value, where a next data sampling is performed only when processing and transmission after each data sampling is performed. The specific procedure is as follows. Firstly, a control unit transmits a measurement command to a ranging chip. The ranging chip controls an infrared light source to emit four modulated pulse. The emitted modulated infrared light signals encounter an obstacle and are reflected. The ranging chip receives the infrared light signals reflected by the obstacle and records magnitudes of the four returned signals respectively, which are used as magnitudes of detection sampling signals having phases of 0 degrees, 90 degrees, 180 degrees and 270 degrees, respectively. The ranging chip performs four detection samplings on a same detection region in the above manner, and acquires the distance value between the ranging chip and the obstacle after calculation.
In the above conventional technology, multiple detections are required for calculating the distance value from a same detection region. In actual applications of the ranging device, distances needs to be detected rapidly. For example, a rotatable scan detection device needs to rotate at a speed of 3 to 5 revolutions per second or even faster, so as to increase a distance measurement speed and a data updating frequency. However, in the conventional detection method where multiple data samplings are required for calculating one distance value, the ranging device needs to remain at a same rotation angle for a period long enough to perform multiple detection samplings and associated calculations in order to acquire one distance value. In a case that the ranging device remains at a same rotation angle for an excessively long period, it is difficult for the ranging device to rotate in a high speed continuously, thus the distance scan and measurement speed is reduced. In a scan ranging device rotating at a high speed, to calculate a distance from one location by multiple samplings may cause inconsistency in targets corresponding to the sampling points, thereby resulting in motion blur, which causes a range error. Further, if the rotatable mechanism remains at a same position for four samplings of each distance measurement, a great vibration may be produced, and a high rotation speed cannot be achieved.
Based on the above deficiency in the conventional technology, a fast scan detection method is provided according to the present disclosure. Particularly, a fast scan detection method using an array photoelectric sensor in a ranging unit is provided according to the present disclosure.